The present invention is directed to real-time updating of location information regarding a communications device, and, more specifically, to automatically updating location information prior to call placement for call routing purposes. Further, when there are multiple location determinations for the same communications device, embodiments of this invention select one of the locations based on differentiation factors.
Many special number services use the location of the calling communications device in order to route the call to an answering point that handles such calls. For example, calls to emergency service numbers (such as “9-1-1” in the US and Canada and “1-1-2” in most of Europe) are routed to a public safety answering point (PSAP) that serves the emergency services zone (ESZ) wherein the calling communications device is located, so that the operator can dispatch local police, fire, ambulance, etc., to the location of the caller.
Currently, there are three types of communications devices that use special number services: landline, wireless and voice over Internet Protocol (VoIP). Landline devices, for which most special number services were devised, are stationary. Hence, a simple database that relates the telephone number to the serving answering point has been and is sufficient for routing special number calls based on the location of the communications device.
Wireless communications devices, by their nature, are intended to be mobile. Several systems have recently been devised to relate the wireless communications device's geographic location to the ESZ in which it is located in real time. Some of these location determination systems are based on having an embedded GPS device in the communications device. Other systems use the known location of the serving cell site and then narrow down the specific location of the wireless communications device using signal strength, radio signal triangulation, etc.
VoIP communications devices, however, have characteristics of both landline and mobile communications devices. Specifically, when in use, VoIP communications devices are connected by wire lines to a data network. However, VoIP communications devices may be disconnected and reconnected in virtually any location of the data network. These VoIP communications devices are considered to be “nomadic.” Some VoIP service providers require that the subscriber of a VoIP communications device register location before the device may be used in a new location. This requirement helps in long-term situations, when the device is not moved frequently. However, if a subscriber encounters an emergency situation while moving about, he or she may not have time to register before making an emergency call.
Further, some VoIP communications devices are wireless, which means that these VoIP communications devices connect to a data network via radio signals at a radio to network interface (e.g., an access point). Such VoIP communications devices are similar to wireless communications devices, but operate in an entirely different manner. Therefore, the location determination systems developed for wireless communications devices do not necessarily work for wireless VoIP communications devices.
A complicating factor to determining the location of a VoIP communications device is that there are competing technologies that uses different methods to determine location. For example, GPS devices are well known in the art and are being incorporated in some VoIP communications devices and wireless communications devices. As is known in the art, GPS devices receive a plurality of satellite signals and resolve the signals into a location. The satellite signals, however, are generally difficult to receive in buildings and urban areas, which limits the effectiveness of GPS-only systems.
A system developed by Rosum, Inc. (www.rosum.com) uses both GPS and television signals to determine location. This system samples local television signals and compares them to the signals received at a known location. The relative difference provides a location of the communications device. By using television signals as well as GPS, this system can operate indoors and in urban areas where GPS signals are not received accurately, if at all.
Another method to determine the location of a communications device is provided by Skyhook Wireless, Inc. (www.skyhook.com). This system uses a plurality of Wi-Fi signals from various known access points to determine location. This system solves the problem of determining location indoors and in urban areas, because Wi-Fi is generally prevalent in these areas. This system is limited, however, to those locations were there are enough known Wi-Fi access points to determine location and by the relatively low Wi-Fi signal strength transmitted from the access point.
A further method to determine the location of a device is provided by S5 (www.s5w.com). This system uses a plurality of relatively low speed, spread spectrum Wi-Fi signals from a source to a plurality of antennas at known positions to determine location. This system works over a longer distance than high-speed Wi-Fi and can work indoors as well as outdoors. Low-speed, spread spectrum Wi-Fi, however, is not widely deployed and thus not available in all areas.
Therefore, a problem in the art of location-based routing of special number calls is that there is no system for selecting one location from a plurality of locations determined by a plurality of location determination methods to update a routing database.